Save hundreds in dealer fees – install this genuine Mercury Marine HOSE, THERMOSTAT HOUSING TO FLUID COOLER yourself. Our parts experts provide guidance if needed, and you get OEM quality at discount pricing.

Designed and manufactured to Mercury Marine OEM standards, this thermostat ensures reliable operation across all engine RPM ranges. Part number 16012 is manufactured to exact Mercury Marine factory specifications for precision installation and optimal performance. Constructed from premium marine-grade materials designed to withstand harsh saltwater and freshwater environments.

Cut-rate alternatives might look similar, but they’re not engineered to Mercury’s exacting standards. Part 16012 delivers consistent performance because it’s built right — the same way Mercury does it at the factory.

Compatible Mercury Marine Engines

FITS: 4-383HP MERCRUISER

• Fits MERCRUISER 4-383HP engines
• Compatible with 9 different HP configurations
• Covers 24 serial number ranges
• Configurations: Outboard
• OEM genuine Mercury Marine part

COMPLETE SERIAL NUMBER COMPATIBILITY:

4HP Models

• 4HP OUTBOARD (Mercruiser): 0B773243-0D714106, 0D714107-0F000877, 0F000878-0F601126, 0B775130-0D714369, 0D714370-0F001219, 0F001220-0F601126

5HP Models

• 5HP OUTBOARD (Mercruiser): 0B774445-0F600999, 0B522506-0B788151, 0B773740-0F600999, 0B514627-0F775199, 0B525982-0F600999, 0B788197-0F024999

175HP Models

• 175HP OUTBOARD (Mercruiser): 0B527955-0B773242

200HP Models

• 200HP OUTBOARD (Mercruiser): 0B525982-0B774444

205HP Models

• 205HP OUTBOARD (Mercruiser): 0B527955-0B775129

230HP Models

• 230HP MIE (Mercruiser): 0B522506-0B788151
• 230HP OUTBOARD (Mercruiser): 0B525982-0B773739

260HP Models

• 260HP OUTBOARD (Mercruiser): 0B525982-0B773739, 0B525982-0B773304, 0B522506-0B788196

350HP Models

• 350HP MAG (Mercruiser): 0D505450-0K040399
• 350HP OUTBOARD (Mercruiser): 0B525982-0F600999, 0F215561-0F820706

383HP Models

• 383HP INBOARD (Mercruiser)

Need help finding your serial number? Check our serial number location guide for step-by-step instructions on locating it on your Mercury engine.

Verification & Support

Questions about part 16012? Use our parts finder tool to verify fitment yourself. Prefer to talk to an expert? Use the contact buttons at the bottom of this page to reach our team by text, call, or email

Family-owned and operated since 1985. Competitive pricing, same-day shipping on most orders.